Buy: Also known as strong buy and "on the recommended list." Needless to say, buy is a recommendation to purchase a specific security.
Sell: Also known as strong sell, it's a recommendation to sell a security or to liquidate an asset.
Hold (Neutral): In general terms, a company with a hold recommendation is expected to perform at the same pace as comparable companies or in line with the market.
Underperform: A recommendation that means a stock is expected to do slightly worse than the overall stock market return. Underperform can also be expressed as "moderate sell," "weak hold," and "underweight."
Outperform: Also known as "moderate buy," "accumulate," "add," and "overweight." Outperform is an analyst recommendation meaning a stock is expected to do slightly better than the market return.